Hang in there Alex;
Unfortunately you got this kind of medical news at a "delicate' age. When it slowly begins to dawn on us that it's now not a case of "Should I ever die' but "WHEN I die'.

And everything can now become a major worry if we let it. Creepy at first, but you get used to this truth and cheerfully move on. (I think that's why us older types get more daring & laid back - we realise time is catching up soon, and we've been 'proper little persons' long enough.
Go to the Quack at once and get checked out. I reckon you'll be told there's nothing to be concerned about.
Everything's going to be just fine. Enjoy yourself and have fun. Time isn't going all that fast. And we're all in the same boat, yes?